...and here I thought this thread was going to be about what do WE, as gardeners, do to survive planting in the heat.
Most of my irises are in pots, and incoming irises go into pots, so it is not too much of a problem for me. I water periodically (well, right now it is more like sporadically) and the irises do okay. The ones that go into the ground are on automatic irrigation 2x/week. If I think they need more water, then I may hit them with the hose.
(As to what
I do about planting in the heat.... I'm avoiding it as much as possible, because every time I do so, I end up with a migraine. That's my excuse for the complete and utter failure of my "one iris, one daylily, one random ornamental a day" plan. Sorry, I just can't handle the heat.)